Cervical radicular pain is described as pain originating in the neck with radiation over the posterior shoulder, upper scapular region, arm, and hand. It is characterized by a combination of sensory, motor, and/or reflex impairment of the neck and upper extremities [16]. In order for pain to be present the dorsal root ganglion must also be compressed or irritated [6]. While it is less common than axial neck pain, it is still quite prevalent occurring in 85 out of 100,000 patients annually [17]. It is most common in the sixth decade of life but can affect all adult patients [16]. Non-compressive causes such as diabetic plexopathies, herpes zoster, primary shoulder disease, upper extremity nerve entrapment, and root avulsion account for a small minority of the total cervical radiculopathy but should be included in the differential diagnosis prior to entertaining the more common causes [5, 7]. Over 90 % of cervical radiculopathies result from direct compression or irritation of the cervical nerve root and dorsal root ganglion. Unlike the lumbar spine, the most common causes of cervical nerve root compression are cervical spondylosis followed by cervical disk herniation [7, 18, 19]. In this setting spondylosis refers to the age related changes of the uncovertebral joint, cervical facet joints, intervertebral disks, and ligamentum flavum all of which contribute to neuroforaminal narrowing. Degeneration and hypertrophy in these cervical structures leads to narrowing of the neuro foramen and results in compressive symptoms to the cervical spinal nerve [5].

Patients suffering from a cervical radiculopathy generally describe a sharp, burning, shooting, and/or electric pain located in the neck, shoulder, arm or hand depending on the affected nerve root (Table 4.3) [7]. Of patients presenting with cervical radiculopathy 99 % complained of arm pain, 85 % had sensory deficits, and 80 % complained of neck pain [20]. The lower cervical spinal levels are most common. The C7 nerve root is involved in 45 to 60 % of patients with C6 accounting for 20 to 25 %. The C5 and C8 spinal nerve roots each account for approximately 10 % of the cases [16]. It should be noted that a C6-7 disk herniation will result in a C7 radiculopathy.

Findings on physical exam may include decreased sensation, upper extremity weakness, and hyporeflexia. Provocative maneuvers including the upper limb tension test (ULTT) , neck distraction, Spurling test, and the shoulder abduction test increase the clinician’s suspicions of a radicular source by exacerbating or relieving the patient’s radicular pain. Of the provocative maneuvers the ULTT is the most sensitive for cervical radiculopathy [5, 21–23].

Plain film radiographs and more advanced imaging modalities for nontraumatic neck pain are rarely helpful and should be reserved for patients with red flag symptoms (Table 4.1) or in patients with pain that last longer than 6 weeks and is unresponsive to conservative treatment [5, 16]. Plain film radiographs offer information regarding congenital abnormalities, disk degeneration, instability, fractures, and sagittal alignment. However, none of these findings, including abnormal curvature, are predictive of more severe underlying diseases [7, 24].

Magnetic resonance images (MRI) is clearly superior to any other imaging modality when assessing changes in the intervertebral disk, nerve root, dorsal root ganglion, spinal cord, the neuro foramen and surrounding soft tissues all of which could account for radicular symptoms (Fig. 4.2), however, there is no direct link between abnormalities seen in these structures and pain. In fact studies have shown abnormal MRI results in 10 to 60 % of asymptomatic patients depending on age [16, 17, 25, 26]. As a result the correct diagnosis of cervical radiculopathy, including the level involved, requires careful layering of all components of the history, physical exam, and imaging studies.

Electromyography (EMG) and nerve conduction tests may be useful when the history, physical exam, and other imaging studies cannot differentiate between a radicular source of pain and other neurological pain generators of the upper extremity (i.e., distal nerve entrapments or plexopathies). In addition, an EMG may be of value when multiple levels of neuroforaminal stenosis are seen on MRI because specific spinal nerve roots can be tested as long as the upper extremity symptoms have been present for greater than 3 weeks [7, 16, 27]. However, mild radiculopathies may have a normal EMG [28].

The cervical facet joint is a common source for axial neck pain accounting for 25 to 65 % of patients suffering from neck pain depending on the selection method [29–33]. In patients suffering from chronic neck pain after a known whiplash injury the prevalence of pain coming from one or more cervical facet joint is 54 to 60 % [34, 35]. As a diarthrotic joint it is susceptible to traumatic, occupational, and age related degenerations resulting in its high prevalence [36]. While all levels of the cervical facets can be sources of pain the most common levels are C2-3 and C5-6. In nearly half the patients suffering from cervical fact mediated pain more than one facet joint was involved [37]. Studies have shown that occupation plays a significant rate in developing neck pain and may be secondary to added stress on the facet joints during prolonged flexion or extension [38, 39].

As with cervical radiculopathy a clinician’s first responsibility is to rule out any serious underlying disease before establishing the diagnosis of cervical facet pain. Part of this evaluation should include questioning the patient about previous trauma, weight loss, night pain, and history of malignancy. Cervical facet pain has been described as a dull or sharp pain in the posterior lateral and dorsal side of the spinal column with radiation into the scapular region, upper shoulders or head depending on the level affected [6, 36]. In some cases the pain may radiate into the upper arm but should not go distal to the elbow unless the facet hypertrophy is also affecting the neuro foramen. Fortunately, pain from the cervical facet joints often follows a specific and clinically recognizable pattern (Fig. 4.3) [6, 37]. The pain is often exacerbated with rotation, flexion, and neck extension. In fact, patient’s first complaint may be pain and stiffness when rotating their neck to look behind them while reversing a car.

The physical exam should include eliminating cervical radiculopathy as well as shoulder pathology as potential pain generators. In addition, a neurologic exam of the upper extremities should be normal in patients with cervical facet disease. Provocative manners that produce pressure and tension on the cervical facets are often helpful. For upper facets (C2-3 and C3-4) rotation of the cervical spine in a flexed position (looking at the floor) may reproduce pain. Movement in the lower facets (C5-6 and C6-7) can be assessed by rotating the cervical spine in an extended position (looking at the ceiling) [36]. In addition, research has demonstrated that pain along the facet column with 4 kg of locally applied pressure is indicative of cervical facet disease [40].

In patients suffering with axial neck pain imaging studies are rarely helpful. Plain film radiographs may exclude tumor, fracture, or other serious systemic disease. In addition, plain films may help establish the degree of degeneration in the cervical facets (Fig. 4.4). While correlation between degeneration seen on imaging and pain symptoms is controversial there are studies showing a relationship between advanced degenerative changes on plain film radiographs and facet mediated pain [36, 41].

Advances in magnetic resonance imaging (MRI) have enabled clinicians to see signs of inflammatory changes in the cervical facet (Fig. 4.4). However, like degeneration in plain film radiographs inflammation does not necessarily correlate to that cervical facet joint(s) being the source of pain. EMG studies are not indicated for axial neck pain.

The most reliable way to establish if the cervical facets are the etiology of a patient’s axial neck pain is by performing diagnostic blocks of the medial branches that supply sensory innervation to each joint. It has been verified that the cervical facet joint is innervated via the medial branches of the rami dorsales from the spinal nerves above and below the joint. For example, to confirm the C6-7 facet joint as painful a small amount (0.25 to 0.5 mls) of local anesthetic is injected under image guidance onto the medial branches of the rami dorsales of C5 and C6. Although invasive this modality can be vital in establishing a clear diagnosis and allow the clinician and patient to consider other minimally invasive treat options for cervical facet pain [13, 33, 36, 40, 42].

The cervical disks are innervated by the sinuvertebral nerves, vertebral nerve, and the cervical sympathetic trunk [43–45]. Degeneration of the cervical disk can result in pain in other areas of the cervical spine (i.e., radiculopathy, uncovertebral joint, and facet joint). However, the cervical disks themselves have been identified as a source of neck pain [46]. The exact incidence of discogenic neck pain is unknown however one study estimated it to be present in 16 % of patients with complaints of neck pain [33].

Patients with neck pain from a discogenic source will complain of a dull aching pain over the midline neck with the level depending on the disk involved. The pain will not radiate unless the disk degeneration has become significant enough to cause nerve root irritation [45]. No physical exam maneuver has been validated to be specific or sensitive for disk mediated pain however, neck distraction may give the examiner some clue that the disk may be involved. Therefore, the history and physical exam center on eliminating other more common sources of neck pain.